Compilare: main.cpp: In function 'void predfs(int, int)': main.cpp:19:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i<v[r].size(); i++) ~^~~~~~~~~~~~ main.cpp: In function 'void dfs(int, int)': main.cpp:31:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i<v[r].size(); i++) ~^~~~~~~~~~~~ main.cpp:45:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i<v[r].size(); i++) ~^~~~~~~~~~~~